Logo
Unionpedia
Communication
Get it on Google Play
New! Download Unionpedia on your Android™ device!
Free
Faster access than browser!
 

Category (mathematics)

Index Category (mathematics)

In mathematics, a category (sometimes called an abstract category to distinguish it from a concrete category) is an algebraic structure similar to a group but without requiring inverse or closure properties. [1]

105 relations: Abelian category, Abelian group, Additive category, Algebraic structure, Allegory (category theory), Antisymmetric relation, Associative property, Automorphism, Bilinear form, Binary operation, Binary relation, Bundle map, Cartesian closed category, Categories for the Working Mathematician, Category of abelian groups, Category of groups, Category of magmas, Category of manifolds, Category of metric spaces, Category of modules, Category of preordered sets, Category of relations, Category of rings, Category of sets, Category of small categories, Category of topological spaces, Category theory, Class (set theory), Closure (mathematics), Cokernel, Commutative diagram, Complete category, Complete partial order, Concrete category, Continuous function, Coproduct, Differentiable manifold, Directed graph, Discrete category, Endomorphism, Enriched category, Epimorphism, Equivalence of categories, Equivalence relation, Fiber bundle, Field (mathematics), Free category, Function (mathematics), Function composition, Functor, ..., Generator (mathematics), GNU Free Documentation License, Group (mathematics), Group action, Group homomorphism, Groupoid, Higher category theory, Identity (mathematics), Identity element, Identity function, Inverse element, Isomorphism, Kernel (category theory), Limit (category theory), Linear map, List of mathematical symbols, Loop (graph theory), Magma (algebra), Mathematics, Metric map, Metric space, Module (mathematics), Module homomorphism, Monoid, Monomorphism, Monotonic function, Morphism, Opposite category, Ordinal number, Partially ordered set, Preadditive category, Preorder, Product (category theory), Quantaloid, Reflexive relation, Ring (mathematics), Ring homomorphism, Samuel Eilenberg, Saunders Mac Lane, Scott continuity, Section (category theory), Semantics (computer science), Set (mathematics), Set theory, Stanford Encyclopedia of Philosophy, Subcategory, Topological space, Topos, Total order, Transitive relation, Tuple, Uniform continuity, Uniform space, Vector space, Vertex (graph theory). Expand index (55 more) »

Abelian category

In mathematics, an abelian category is a category in which morphisms and objects can be added and in which kernels and cokernels exist and have desirable properties.

New!!: Category (mathematics) and Abelian category · See more »

Abelian group

In abstract algebra, an abelian group, also called a commutative group, is a group in which the result of applying the group operation to two group elements does not depend on the order in which they are written.

New!!: Category (mathematics) and Abelian group · See more »

Additive category

In mathematics, specifically in category theory, an additive category is a preadditive category C admitting all finitary biproducts.

New!!: Category (mathematics) and Additive category · See more »

Algebraic structure

In mathematics, and more specifically in abstract algebra, an algebraic structure on a set A (called carrier set or underlying set) is a collection of finitary operations on A; the set A with this structure is also called an algebra.

New!!: Category (mathematics) and Algebraic structure · See more »

Allegory (category theory)

In the mathematical field of category theory, an allegory is a category that has some of the structure of the category of sets and binary relations between them.

New!!: Category (mathematics) and Allegory (category theory) · See more »

Antisymmetric relation

In mathematics, a binary relation R on a set X is anti-symmetric if there is no pair of distinct elements of X each of which is related by R to the other.

New!!: Category (mathematics) and Antisymmetric relation · See more »

Associative property

In mathematics, the associative property is a property of some binary operations.

New!!: Category (mathematics) and Associative property · See more »

Automorphism

In mathematics, an automorphism is an isomorphism from a mathematical object to itself.

New!!: Category (mathematics) and Automorphism · See more »

Bilinear form

In mathematics, more specifically in abstract algebra and linear algebra, a bilinear form on a vector space V is a bilinear map, where K is the field of scalars.

New!!: Category (mathematics) and Bilinear form · See more »

Binary operation

In mathematics, a binary operation on a set is a calculation that combines two elements of the set (called operands) to produce another element of the set.

New!!: Category (mathematics) and Binary operation · See more »

Binary relation

In mathematics, a binary relation on a set A is a set of ordered pairs of elements of A. In other words, it is a subset of the Cartesian product A2.

New!!: Category (mathematics) and Binary relation · See more »

Bundle map

In mathematics, a bundle map (or bundle morphism) is a morphism in the category of fiber bundles.

New!!: Category (mathematics) and Bundle map · See more »

Cartesian closed category

In category theory, a category is considered Cartesian closed if, roughly speaking, any morphism defined on a product of two objects can be naturally identified with a morphism defined on one of the factors.

New!!: Category (mathematics) and Cartesian closed category · See more »

Categories for the Working Mathematician

Categories for the Working Mathematician (CWM) is a textbook in category theory written by American mathematician Saunders Mac Lane, who cofounded the subject together with Samuel Eilenberg.

New!!: Category (mathematics) and Categories for the Working Mathematician · See more »

Category of abelian groups

In mathematics, the category Ab has the abelian groups as objects and group homomorphisms as morphisms.

New!!: Category (mathematics) and Category of abelian groups · See more »

Category of groups

In mathematics, the category Grp has the class of all groups for objects and group homomorphisms for morphisms.

New!!: Category (mathematics) and Category of groups · See more »

Category of magmas

In mathematics, the category of magmas, denoted Mag, has as objects sets with a binary operation, and morphisms given by homomorphisms of operations (in the universal algebra sense).

New!!: Category (mathematics) and Category of magmas · See more »

Category of manifolds

In mathematics, the category of manifolds, often denoted Manp, is the category whose objects are manifolds of smoothness class Cp and whose morphisms are p-times continuously differentiable maps.

New!!: Category (mathematics) and Category of manifolds · See more »

Category of metric spaces

In category-theoretic mathematics, Met is a category that has metric spaces as its objects and metric maps (continuous functions between metric spaces that do not increase any pairwise distance) as its morphisms.

New!!: Category (mathematics) and Category of metric spaces · See more »

Category of modules

In algebra, given a ring R, the category of left modules over R is the category whose objects are all left modules over R and whose morphisms are all module homomorphisms between left R-modules.

New!!: Category (mathematics) and Category of modules · See more »

Category of preordered sets

The category Ord has preordered sets as objects and order-preserving functions as morphisms.

New!!: Category (mathematics) and Category of preordered sets · See more »

Category of relations

In mathematics, the category Rel has the class of sets as objects and binary relations as morphisms.

New!!: Category (mathematics) and Category of relations · See more »

Category of rings

In mathematics, the category of rings, denoted by Ring, is the category whose objects are rings (with identity) and whose morphisms are ring homomorphisms (preserving the identity).

New!!: Category (mathematics) and Category of rings · See more »

Category of sets

In the mathematical field of category theory, the category of sets, denoted as Set, is the category whose objects are sets.

New!!: Category (mathematics) and Category of sets · See more »

Category of small categories

In mathematics, specifically in category theory, the category of small categories, denoted by Cat, is the category whose objects are all small categories and whose morphisms are functors between categories.

New!!: Category (mathematics) and Category of small categories · See more »

Category of topological spaces

In mathematics, the category of topological spaces, often denoted Top, is the category whose objects are topological spaces and whose morphisms are continuous maps or some other variant; for example, objects are often assumed to be compactly generated.

New!!: Category (mathematics) and Category of topological spaces · See more »

Category theory

Category theory formalizes mathematical structure and its concepts in terms of a labeled directed graph called a category, whose nodes are called objects, and whose labelled directed edges are called arrows (or morphisms).

New!!: Category (mathematics) and Category theory · See more »

Class (set theory)

In set theory and its applications throughout mathematics, a class is a collection of sets (or sometimes other mathematical objects) that can be unambiguously defined by a property that all its members share.

New!!: Category (mathematics) and Class (set theory) · See more »

Closure (mathematics)

A set has closure under an operation if performance of that operation on members of the set always produces a member of the same set; in this case we also say that the set is closed under the operation.

New!!: Category (mathematics) and Closure (mathematics) · See more »

Cokernel

In mathematics, the cokernel of a linear mapping of vector spaces f: X → Y is the quotient space Y/im(f) of the codomain of f by the image of f. The dimension of the cokernel is called the corank of f. Cokernels are dual to the kernels of category theory, hence the name: the kernel is a subobject of the domain (it maps to the domain), while the cokernel is a quotient object of the codomain (it maps from the codomain).

New!!: Category (mathematics) and Cokernel · See more »

Commutative diagram

The commutative diagram used in the proof of the five lemma. In mathematics, and especially in category theory, a commutative diagram is a diagram such that all directed paths in the diagram with the same start and endpoints lead to the same result.

New!!: Category (mathematics) and Commutative diagram · See more »

Complete category

In mathematics, a complete category is a category in which all small limits exist.

New!!: Category (mathematics) and Complete category · See more »

Complete partial order

In mathematics, the phrase complete partial order is variously used to refer to at least three similar, but distinct, classes of partially ordered sets, characterized by particular completeness properties.

New!!: Category (mathematics) and Complete partial order · See more »

Concrete category

In mathematics, a concrete category is a category that is equipped with a faithful functor to the category of sets (or sometimes to another category, see Relative concreteness below).

New!!: Category (mathematics) and Concrete category · See more »

Continuous function

In mathematics, a continuous function is a function for which sufficiently small changes in the input result in arbitrarily small changes in the output.

New!!: Category (mathematics) and Continuous function · See more »

Coproduct

In category theory, the coproduct, or categorical sum, is a category-theoretic construction which includes as examples the disjoint union of sets and of topological spaces, the free product of groups, and the direct sum of modules and vector spaces.

New!!: Category (mathematics) and Coproduct · See more »

Differentiable manifold

In mathematics, a differentiable manifold (also differential manifold) is a type of manifold that is locally similar enough to a linear space to allow one to do calculus.

New!!: Category (mathematics) and Differentiable manifold · See more »

Directed graph

In mathematics, and more specifically in graph theory, a directed graph (or digraph) is a graph that is a set of vertices connected by edges, where the edges have a direction associated with them.

New!!: Category (mathematics) and Directed graph · See more »

Discrete category

In mathematics, in the field of category theory, a discrete category is a category whose only morphisms are the identity morphisms: Since by axioms, there is always the identity morphism between the same object, we can express the above as condition on the cardinality of the hom-set Some authors prefer a weaker notion, where a discrete category merely needs to be equivalent to such a category.

New!!: Category (mathematics) and Discrete category · See more »

Endomorphism

In mathematics, an endomorphism is a morphism (or homomorphism) from a mathematical object to itself.

New!!: Category (mathematics) and Endomorphism · See more »

Enriched category

In category theory, a branch of mathematics, an enriched category generalizes the idea of a category by replacing hom-sets with objects from a general monoidal category.

New!!: Category (mathematics) and Enriched category · See more »

Epimorphism

In category theory, an epimorphism (also called an epic morphism or, colloquially, an epi) is a morphism f: X → Y that is right-cancellative in the sense that, for all morphisms, Epimorphisms are categorical analogues of surjective functions (and in the category of sets the concept corresponds to the surjective functions), but it may not exactly coincide in all contexts; for example, the inclusion \mathbb\to\mathbb is a ring-epimorphism.

New!!: Category (mathematics) and Epimorphism · See more »

Equivalence of categories

In category theory, an abstract branch of mathematics, an equivalence of categories is a relation between two categories that establishes that these categories are "essentially the same".

New!!: Category (mathematics) and Equivalence of categories · See more »

Equivalence relation

In mathematics, an equivalence relation is a binary relation that is reflexive, symmetric and transitive.

New!!: Category (mathematics) and Equivalence relation · See more »

Fiber bundle

In mathematics, and particularly topology, a fiber bundle (or, in British English, fibre bundle) is a space that is locally a product space, but globally may have a different topological structure.

New!!: Category (mathematics) and Fiber bundle · See more »

Field (mathematics)

In mathematics, a field is a set on which addition, subtraction, multiplication, and division are defined, and behave as when they are applied to rational and real numbers.

New!!: Category (mathematics) and Field (mathematics) · See more »

Free category

In mathematics, the free category or path category generated by a directed graph or quiver is the category that results from freely concatenating arrows together, whenever the target of one arrow is the source of the next.

New!!: Category (mathematics) and Free category · See more »

Function (mathematics)

In mathematics, a function was originally the idealization of how a varying quantity depends on another quantity.

New!!: Category (mathematics) and Function (mathematics) · See more »

Function composition

In mathematics, function composition is the pointwise application of one function to the result of another to produce a third function.

New!!: Category (mathematics) and Function composition · See more »

Functor

In mathematics, a functor is a map between categories.

New!!: Category (mathematics) and Functor · See more »

Generator (mathematics)

In mathematics and physics, the term generator or generating set may refer to any of a number of related concepts.

New!!: Category (mathematics) and Generator (mathematics) · See more »

GNU Free Documentation License

The GNU Free Documentation License (GNU FDL or simply GFDL) is a copyleft license for free documentation, designed by the Free Software Foundation (FSF) for the GNU Project.

New!!: Category (mathematics) and GNU Free Documentation License · See more »

Group (mathematics)

In mathematics, a group is an algebraic structure consisting of a set of elements equipped with an operation that combines any two elements to form a third element and that satisfies four conditions called the group axioms, namely closure, associativity, identity and invertibility.

New!!: Category (mathematics) and Group (mathematics) · See more »

Group action

In mathematics, an action of a group is a formal way of interpreting the manner in which the elements of the group correspond to transformations of some space in a way that preserves the structure of that space.

New!!: Category (mathematics) and Group action · See more »

Group homomorphism

In mathematics, given two groups, (G, ∗) and (H, ·), a group homomorphism from (G, ∗) to (H, ·) is a function h: G → H such that for all u and v in G it holds that where the group operation on the left hand side of the equation is that of G and on the right hand side that of H. From this property, one can deduce that h maps the identity element eG of G to the identity element eH of H, and it also maps inverses to inverses in the sense that Hence one can say that h "is compatible with the group structure".

New!!: Category (mathematics) and Group homomorphism · See more »

Groupoid

In mathematics, especially in category theory and homotopy theory, a groupoid (less often Brandt groupoid or virtual group) generalises the notion of group in several equivalent ways.

New!!: Category (mathematics) and Groupoid · See more »

Higher category theory

In mathematics, higher category theory is the part of category theory at a higher order, which means that some equalities are replaced by explicit arrows in order to be able to explicitly study the structure behind those equalities.

New!!: Category (mathematics) and Higher category theory · See more »

Identity (mathematics)

In mathematics an identity is an equality relation A.

New!!: Category (mathematics) and Identity (mathematics) · See more »

Identity element

In mathematics, an identity element or neutral element is a special type of element of a set with respect to a binary operation on that set, which leaves other elements unchanged when combined with them.

New!!: Category (mathematics) and Identity element · See more »

Identity function

Graph of the identity function on the real numbers In mathematics, an identity function, also called an identity relation or identity map or identity transformation, is a function that always returns the same value that was used as its argument.

New!!: Category (mathematics) and Identity function · See more »

Inverse element

In abstract algebra, the idea of an inverse element generalises concepts of a negation (sign reversal) in relation to addition, and a reciprocal in relation to multiplication.

New!!: Category (mathematics) and Inverse element · See more »

Isomorphism

In mathematics, an isomorphism (from the Ancient Greek: ἴσος isos "equal", and μορφή morphe "form" or "shape") is a homomorphism or morphism (i.e. a mathematical mapping) that can be reversed by an inverse morphism.

New!!: Category (mathematics) and Isomorphism · See more »

Kernel (category theory)

In category theory and its applications to other branches of mathematics, kernels are a generalization of the kernels of group homomorphisms, the kernels of module homomorphisms and certain other kernels from algebra.

New!!: Category (mathematics) and Kernel (category theory) · See more »

Limit (category theory)

In category theory, a branch of mathematics, the abstract notion of a limit captures the essential properties of universal constructions such as products, pullbacks and inverse limits.

New!!: Category (mathematics) and Limit (category theory) · See more »

Linear map

In mathematics, a linear map (also called a linear mapping, linear transformation or, in some contexts, linear function) is a mapping between two modules (including vector spaces) that preserves (in the sense defined below) the operations of addition and scalar multiplication.

New!!: Category (mathematics) and Linear map · See more »

List of mathematical symbols

This is a list of symbols used in all branches of mathematics to express a formula or to represent a constant.

New!!: Category (mathematics) and List of mathematical symbols · See more »

Loop (graph theory)

In graph theory, a loop (also called a self-loop or a "buckle") is an edge that connects a vertex to itself.

New!!: Category (mathematics) and Loop (graph theory) · See more »

Magma (algebra)

In abstract algebra, a magma (or groupoid; not to be confused with groupoids in category theory) is a basic kind of algebraic structure.

New!!: Category (mathematics) and Magma (algebra) · See more »

Mathematics

Mathematics (from Greek μάθημα máthēma, "knowledge, study, learning") is the study of such topics as quantity, structure, space, and change.

New!!: Category (mathematics) and Mathematics · See more »

Metric map

In the mathematical theory of metric spaces, a metric map is a function between metric spaces that does not increase any distance (such functions are always continuous).

New!!: Category (mathematics) and Metric map · See more »

Metric space

In mathematics, a metric space is a set for which distances between all members of the set are defined.

New!!: Category (mathematics) and Metric space · See more »

Module (mathematics)

In mathematics, a module is one of the fundamental algebraic structures used in abstract algebra.

New!!: Category (mathematics) and Module (mathematics) · See more »

Module homomorphism

In algebra, a module homomorphism is a function between modules that preserves module structures.

New!!: Category (mathematics) and Module homomorphism · See more »

Monoid

In abstract algebra, a branch of mathematics, a monoid is an algebraic structure with a single associative binary operation and an identity element.

New!!: Category (mathematics) and Monoid · See more »

Monomorphism

In the context of abstract algebra or universal algebra, a monomorphism is an injective homomorphism.

New!!: Category (mathematics) and Monomorphism · See more »

Monotonic function

In mathematics, a monotonic function (or monotone function) is a function between ordered sets that preserves or reverses the given order.

New!!: Category (mathematics) and Monotonic function · See more »

Morphism

In mathematics, a morphism is a structure-preserving map from one mathematical structure to another one of the same type.

New!!: Category (mathematics) and Morphism · See more »

Opposite category

In category theory, a branch of mathematics, the opposite category or dual category Cop of a given category C is formed by reversing the morphisms, i.e. interchanging the source and target of each morphism.

New!!: Category (mathematics) and Opposite category · See more »

Ordinal number

In set theory, an ordinal number, or ordinal, is one generalization of the concept of a natural number that is used to describe a way to arrange a collection of objects in order, one after another.

New!!: Category (mathematics) and Ordinal number · See more »

Partially ordered set

In mathematics, especially order theory, a partially ordered set (also poset) formalizes and generalizes the intuitive concept of an ordering, sequencing, or arrangement of the elements of a set.

New!!: Category (mathematics) and Partially ordered set · See more »

Preadditive category

In mathematics, specifically in category theory, a preadditive category is a category that is enriched over the monoidal category of abelian groups.

New!!: Category (mathematics) and Preadditive category · See more »

Preorder

In mathematics, especially in order theory, a preorder or quasiorder is a binary relation that is reflexive and transitive.

New!!: Category (mathematics) and Preorder · See more »

Product (category theory)

In category theory, the product of two (or more) objects in a category is a notion designed to capture the essence behind constructions in other areas of mathematics such as the cartesian product of sets, the direct product of groups, the direct product of rings and the product of topological spaces.

New!!: Category (mathematics) and Product (category theory) · See more »

Quantaloid

In mathematics, a quantaloid is a category enriched over the category Sup of suplattices.

New!!: Category (mathematics) and Quantaloid · See more »

Reflexive relation

In mathematics, a binary relation R over a set X is reflexive if every element of X is related to itself.

New!!: Category (mathematics) and Reflexive relation · See more »

Ring (mathematics)

In mathematics, a ring is one of the fundamental algebraic structures used in abstract algebra.

New!!: Category (mathematics) and Ring (mathematics) · See more »

Ring homomorphism

In ring theory or abstract algebra, a ring homomorphism is a function between two rings which respects the structure.

New!!: Category (mathematics) and Ring homomorphism · See more »

Samuel Eilenberg

Samuel Eilenberg (September 30, 1913 – January 30, 1998) was a Polish-born American mathematician who co-founded category theory with Saunders Mac Lane.

New!!: Category (mathematics) and Samuel Eilenberg · See more »

Saunders Mac Lane

Saunders Mac Lane (4 August 1909 – 14 April 2005) was an American mathematician who co-founded category theory with Samuel Eilenberg.

New!!: Category (mathematics) and Saunders Mac Lane · See more »

Scott continuity

In mathematics, given two partially ordered sets P and Q, a function f \colon P \rightarrow Q between them is Scott-continuous (named after the mathematician Dana Scott) if it preserves all directed suprema, i.e. if for every directed subset D of P with supremum in P its image has a supremum in Q, and that supremum is the image of the supremum of D: that is, \sqcup f.

New!!: Category (mathematics) and Scott continuity · See more »

Section (category theory)

In category theory, a branch of mathematics, a section is a right inverse of some morphism.

New!!: Category (mathematics) and Section (category theory) · See more »

Semantics (computer science)

In programming language theory, semantics is the field concerned with the rigorous mathematical study of the meaning of programming languages.

New!!: Category (mathematics) and Semantics (computer science) · See more »

Set (mathematics)

In mathematics, a set is a collection of distinct objects, considered as an object in its own right.

New!!: Category (mathematics) and Set (mathematics) · See more »

Set theory

Set theory is a branch of mathematical logic that studies sets, which informally are collections of objects.

New!!: Category (mathematics) and Set theory · See more »

Stanford Encyclopedia of Philosophy

The Stanford Encyclopedia of Philosophy (SEP) combines an online encyclopedia of philosophy with peer-reviewed publication of original papers in philosophy, freely accessible to Internet users.

New!!: Category (mathematics) and Stanford Encyclopedia of Philosophy · See more »

Subcategory

In mathematics, a subcategory of a category C is a category S whose objects are objects in C and whose morphisms are morphisms in C with the same identities and composition of morphisms.

New!!: Category (mathematics) and Subcategory · See more »

Topological space

In topology and related branches of mathematics, a topological space may be defined as a set of points, along with a set of neighbourhoods for each point, satisfying a set of axioms relating points and neighbourhoods.

New!!: Category (mathematics) and Topological space · See more »

Topos

In mathematics, a topos (plural topoi or, or toposes) is a category that behaves like the category of sheaves of sets on a topological space (or more generally: on a site).

New!!: Category (mathematics) and Topos · See more »

Total order

In mathematics, a linear order, total order, simple order, or (non-strict) ordering is a binary relation on some set X, which is antisymmetric, transitive, and a connex relation.

New!!: Category (mathematics) and Total order · See more »

Transitive relation

In mathematics, a binary relation over a set is transitive if whenever an element is related to an element and is related to an element then is also related to.

New!!: Category (mathematics) and Transitive relation · See more »

Tuple

In mathematics, a tuple is a finite ordered list (sequence) of elements.

New!!: Category (mathematics) and Tuple · See more »

Uniform continuity

In mathematics, a function f is uniformly continuous if, roughly speaking, it is possible to guarantee that f(x) and f(y) be as close to each other as we please by requiring only that x and y are sufficiently close to each other; unlike ordinary continuity, the maximum distance between f(x) and f(y) cannot depend on x and y themselves.

New!!: Category (mathematics) and Uniform continuity · See more »

Uniform space

In the mathematical field of topology, a uniform space is a set with a uniform structure.

New!!: Category (mathematics) and Uniform space · See more »

Vector space

A vector space (also called a linear space) is a collection of objects called vectors, which may be added together and multiplied ("scaled") by numbers, called scalars.

New!!: Category (mathematics) and Vector space · See more »

Vertex (graph theory)

In mathematics, and more specifically in graph theory, a vertex (plural vertices) or node is the fundamental unit of which graphs are formed: an undirected graph consists of a set of vertices and a set of edges (unordered pairs of vertices), while a directed graph consists of a set of vertices and a set of arcs (ordered pairs of vertices).

New!!: Category (mathematics) and Vertex (graph theory) · See more »

Redirects here:

Abstract category, Category (category theory), Category (math), Category (maths), Large category, Locally small category, Mathematical objekt, Object (category theory), Small category.

References

[1] https://en.wikipedia.org/wiki/Category_(mathematics)

OutgoingIncoming
Hey! We are on Facebook now! »